Three-storey curved steel staircase | Bosch
2023, Zuchwil
For the new building of Bosch Switzerland in Zuchwil, operated carbon-neutrally, METALLART realized a sophisticated curved steel staircase spanning four levels (ground floor to 3rd floor). The building, constructed in modern timber design, merges sustainability with technical precision while the sculptural staircase serves as the architectural centerpiece.
The three-storey, seven-flight curved steel staircase seamlessly connects the levels, creating a striking vertical circulation element with a high-quality experience for occupants.
Curved steel staircase with parapet-high stringers
The evenly curved steel staircase was designed as a parapet-high stringer staircase with flat steel stringers on both sides, serving as fall protection and emphasizing its clean lines.
A technical highlight of this curved steel staircase is its smooth, dimensionally stable steel soffit cladding, seamlessly welded between the stringers and precisely following the helical geometry, resulting in a monolithic appearance.
The entire steel structure was finished with a high-quality NCS coating, providing a durable and resilient surface.
Structural optimization in timber construction
The connection of the curved steel staircase to the timber load-bearing structure imposed higher demands on structural stability and vibration performance. Compared to installation on concrete ceilings, mounting on timber beams requires particularly precise structural coordination.
The steel soffit provides additional structural reinforcement resulting in excellent vibration performance and minimized noise levels.
The staircase was delivered in multiple prefabricated elements. On site, the steel staircase was precisely welded, and all welds were carefully finished to ensure a completely uniform surface for the subsequent NCS final coating.
Material Mix & Design
This curved steel staircase thrives on a striking material contrast:
White-painted steel meets solid oak treads with continuous slats. The warm wood tone creates a deliberate contrast to the clean steel structure.
Subtly integrated anti-slip strips made of black neoprene provide safety without compromising the staircase’s elegant lines.
Insights
Project details
- Balustrade stringer staircase from ground floor to 3rd floor
- 7-flight, evenly curved
- Stainless steel handrail on both sides
- Integrated light cove for LED lighting
- High-quality NCS final coating
- Verifiable staircase structural calculation
- Vibration analysis
- Seamlessly welded, following the curved flight
- Higher static strength and improved vibration behavior
- Monolithic overall appearance
- Horizontally welded flat steel on top
- Vertically welded flat steel profile
- Connections at entry and exit with tubular profile extending from the handrail down to finished floor level (FFL)
Architecture
Itten+Brechbühl AG, Bern
Photos
Bosch Schweiz
